Suppressor of K+ transport growth defect 1 (SKD1) interactswith RING-type ubiquitin ligase and sucrose non-fermenting1-related protein kinase (SnRK1) in the halophyte ice plant

SKD1 (suppressor of K+ transport growth defect 1) is an AAA-type ATPase that functions as a molecular motor. It was previously shown that SKD1 accumulates in epidermal bladder cells of the halophyte Mesembryanthemum crystallinum. SKD1 knock-down Arabidopsis mutants showed an imbalanced Na+/K+ ratio under salt stress. Two enzymes involved in protein post-translational modifications that physically interacted with McSKD1 were identified. McCPN1 (copine 1), a RING-type ubiquitin ligase, has an N-terminal myristoylation site that links to the plasma membrane, a central copine domain that interacts with McSKD1, and a C-terminal RING domain that catalyses protein ubiquitination. In vitro ubiquitination assay demonstrated that McCPN1 was capable of mediating ubiquitination of McSKD1. McSnRK1 (sucrose non-fermenting 1-related protein kinase) is a Ser/Thr protein kinase that contains an N-terminal STKc catalytic domain to phosphorylate McSKD1, and C-terminal UBA and KA1 domains to interact with McSKD1. The transcript and protein levels of McSnRK1 increased as NaCl concentrations increased. The formation of an SKD1–SnRK1–CPN1 ternary complex was demonstrated by yeast three-hybrid and bimolecular fluorescence complementation. It was found that McSKD1 preferentially interacts with McSnRK1 in the cytosol, and salt induced the re-distribution of McSKD1 and McSnRK1 towards the plasma membrane via the microtubule cytoskeleton and subsequently interacted with RING-type E3 McCPN1. The potential effects of ubiquitination and phosphorylation on McSKD1, such as changes in the ATPase activity and cellular localization, and how they relate to the functions of SKD1 in the maintenance of Na+/K+ homeostasis under salt stress, are discussed

Arsonium and phosphonium-functionalized gold nanoparticles for mitochondria targeted therapeutics

This thesis presents a body of original research describing the synthesis, characterisation and biological properties of novel arsonium- and phosphonium- alkylthiosulfate zwitterions and thioacetate salts and gold nanoparticles functionalized with triphenylarsoniumpropylthiolate ligands. Chapter 1 presents a systematic literature review of the preparation of functionalized gold nanoparticles, their biomedical properties, the biological applications of phosphonium and arsonium ions and phosphonium-functionalized nanomaterials. Details of the analytical methods employed to characterize all the compounds produced in this study are outlined in chapter 2. Chapter 3 reports the synthesis of the triphenylarsoniopropylthiosulfate zwitterion and ω- thioacetylpropyl(triphenyl)arsonium bromide salt. Both compounds have been characterized spectroscopically and by single crystal X-ray diffraction. The thiosulfate group of the triphenylarsoniopropylthiosulfate zwitterion and the thioacetate group of the ω- thioacetylpropyl(triphenyl)arsonium salt undergo reductive cleavage, forming the corresponding triphenylarsoniumpropylthiolate ions that attach to the surface of gold in a modification of the established Brust-Schiffrin method for preparing gold nanoparticles. TEM studies show the triphenylarsonium-functionalized gold nanoparticles to be spherical with diameters of c.a. 3nm. The presence of the triphenylarsonium groups has been confirmed by Raman and XPS spectroscopy and mass spectrometry. It also describes the synthesis, characterisation and biological properties of a family of phosphoniopropylthiosulfate zwitterions and ω-thioacetylpropyl(triaryl)phosphonium salts derived from tri(4-methoxyphenyl)phosphine, tri(2,6-dimethoxyphenyl)phosphine and tri(2,4,6-trimethoxyphenyl)phosphine. The IC50 values of the triphenylarsoniopropylthiosulfate zwitterion, ω-thioacetylpropyl- (triphenyl)arsonium bromide salt, triphenylarsonium-functionalized gold nanoparticles and family of phosphoniopropylthiosulfate zwitterions and ω- thioacetylpropyl(triaryl)phosphonium salts derived from tri(4-methoxyphenyl)phosphine, tri(2,6-dimethoxyphenyl)phosphine and tri(2,4,6-trimethoxyphenyl)phosphine have been determined against PC3 prostate cancer cells using MTT and CellTiter-Glo assays and are reported in Chapter 4. The uptake of the triphenylarsonium-functionalized gold nanoparticles by PC3 and Human Fibroblast cells has also been determined by ICP-OES spectroscopy

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

The complete sequence of human chromosome 5

Chromosome 5 is one of the largest human chromosomes yet has one of the lowest gene densities. This is partially explained by numerous gene-poor regions that display a remarkable degree of noncoding and syntenic conservation with non-mammalian vertebrates, suggesting they are functionally constrained. In total, we compiled 177.7 million base pairs of highly accurate finished sequence containing 923 manually curated protein-encoding genes including the protocadherin and interleukin gene families and the first complete versions of each of the large chromosome 5 specific internal duplications. These duplications are very recent evolutionary events and play a likely mechanistic role, since deletions of these regions are the cause of debilitating disorders including spinal muscular atrophy (SMA)

Influences of Land Use Change on Baseflow in Mountainous Watersheds

It is crucial for effective water resource management in a watershed that the relationship between land use changes and baseflow. This study quantifies the influence of land use changes on the baseflow dynamics using a hydrological model and partial least-squares (PLS) regression in the Upper Du Watershed (8961 km2), China. Our study suggests that forest can be a major factor with a negative impact on the baseflow. Additionally, farmland and urban land have second-order negative effects on the baseflow dynamics. Baseflow increases when forest is replaced by farmland because the evapotranspiration (ET), associated with baseflow recession, is weaker and shorter in duration in the farmland than in the forest. The conversion of forest to urban land increases baseflow owing to the presence of non-contributing impervious surfaces in urban areas, which prevents the urban land from intercepting the baseflow discharge. These results indicate that the baseflow dynamics are closely associated with varying land use types within a watershed. Thus, this study is intended to provide a deeper understanding of the baseflow processes and useful quantitative information on land use factors in watersheds, enabling more informed decision-making in forest and watershed management

The characteristics of extreme erosion events in a small mountainous watershed.

A large amount of soil loss is caused by a small number of extreme events that are mainly responsible for the time compression of geomorphic processes. The aim of this study was to analyze suspended sediment transport during extreme erosion events in a mountainous watershed. Field measurements were conducted in Wangjiaqiao, a small agricultural watershed (16.7 km(2)) in the Three Gorges Area (TGA) of China. Continuous records were used to analyze suspended sediment transport regimes and assess the sediment loads of 205 rainfall-runoff events during a period of 16 hydrological years (1989-2004). Extreme events were defined as the largest events, ranked in order of their absolute magnitude (representing the 95(th) percentile). Ten extreme erosion events from 205 erosion events, representing 83.8% of the total suspended sediment load, were selected for study. The results of canonical discriminant analysis indicated that extreme erosion events are characterized by high maximum flood-suspended sediment concentrations, high runoff coefficients, and high flood peak discharge, which could possibly be explained by the transport of deposited sediment within the stream bed during previous events or bank collapses

Mixed artificial grasslands with more roots improved mine soil infiltration capacity

Soil water is one of the critical limiting factors in achieving sustainable revegetation. Soil infiltration capacity plays a vital role in determining the inputs from precipitation and enhancing water storage, which are important for the maintenance and survival of vegetation patches in arid and semi-arid areas. Our study investigated the effects of different artificial grasslands on soil physical properties and soil infiltration capacity. The artificial grasslands were Medicago sativa, Astragalus adsurgens, Agropyron mongolicum, Lespedeza davurica, Bromus inermis, Hedysarum scoparium, A. mongolicum + Artemisia desertorum, A. adsurgens + A. desertorum and M. sativa + B. inermis. The soil infiltration capacity index (SICI), which was based on the average infiltration rate of stage I (AIRSI) and the average infiltration rate of stage III (AIRS III), was higher (indicating that the infiltration capacity was greater) under the artificial grasslands than that of the bare soil. The SICI of the A. adsurgens + A. desertorum grassland had the highest value (1.48) and bare soil ( 0.59) had the lowest value. It was evident that artificial grassland could improve soil infiltration capacity. We also used principal component analysis (PCA) to determine that the main factors that affected SICI were the soil water content at a depth of 20 cm (SWC20), the below-ground root biomasses at depths of 10 and 30 cm (BGB10, BGB30), the capillary porosity at a depth of 10 cm (CP10) and the noncapillary porosity at a depth of 20 cm (NCP20). Our study suggests that the use of Legume-poaceae mixtures and Legume-shrub mixtures to create grasslands provided an effective ecological restoration approach to improve soil infiltration properties due to their greater root biomasses. Furthermore, soil water content, below-ground root biomass, soil capillary porosity and soil non-capillary porosity were the main factors that affect the soil infiltration capacity.<br style="orphans: 2; text-align: -webkit-auto; widows: 2;" /

Flood variables and associated abbreviations used in the statistical analysis of the rainfall–runoff-suspended sediment transport relations.

<p>Flood variables and associated abbreviations used in the statistical analysis of the rainfall–runoff-suspended sediment transport relations.</p

Data on the canonical discriminant functions (cdf).

<p>The highest correlations of the variables with the functions are indicated with *.</p